The wikipedia page for idealism doesn't even contain the string "liber" expect in the link list at the bottom. The wiki page for liberalism contains "ideali" in one remark that Kant was an idealist (in the abstract philosophical sense) and mentions conservative criticism that liberal ideas were "idealistic".

World domination fantasies aren't liberal and they are idealistic only if formulated by very stupid people. No wonder that the map in question doens't look like the product of a liberal mind to me and I also very much doubt that it is a product of idealism.

Kang Seung Jae is fighting windmills. And as we know his own plans for "world map improvement" have similar dimensions.